Question 1035547
Perimeter is the sum of all three sides.
Let's call the missing side x.  Then we can write
x + 5m-7 + 2m+5 = 24m-6
x + 7m-2 = 24m-6
Now subtract 7m and add 2...we get
x - 2 = 17m-6
x = 17m-4
the third side...